Abrasive wheel mount



Aug. l, l933. T1 AR5SON 1,920,204

ABRASIVE WHEEL MOUNT Filed May l2, 1930 -J 2 WITNESSES 27 NvENToR 1/www THURE LARSSON ATT NEY Patented Aug. 1, 1933 PATENT OFFICE ABRASIVE WHEEL MOUNT Thure Larsson, Worcester, Mass., assignor Norton Company, Worcester, Mass., a Corporation of Massachusetts Application May 12, 1930. serial No. 451,699

6 Claims..

This invention relates to a supporting and centering means for grinding wheels, and is particularly adapted for quickly and accurately centering large abrasive wheels of great weight, such as those used in the paper industry to grind Wood to pulp, commonly called pulpstones.

As the art of grinding has advanced, industry has demanded larger and faster cutting abrasive wheels until it is now a common practice to produce a grinding wheel five or six feet in diameter which has an equally great width of face and weighs many tons. Abrasive wheels of this type revolve at a high surface rate and are widely used in the paper industry to grind logs to wood pulp from which a large portion of the worlds paper supply is manufactured. Since these massive grinding wheels are required to rotate at such a high rate of speed, it is a matter of utmost importance that each grinding wheel be accurately centered and balanced upon its respective shaft. It has been found by experiment that if a massive grinding wheel of the aforementioned type weighing many tons is rotated oif center` and out of balance even to the extent of a few pounds, it will vibrate sufficiently to be impractical and unsafe for use.

Grinding wheels are ordinarily supported in one cf three ways for rotation with their respective shafts. Monolithic wheels are usually hushed with a soft metal, such as lead or babbitt, which may be cast within the wheel core about an axially positioned stud or mandrel having the same diameter as the shaft upon which the grinding wheel is to be mounted. This method of wheel mounting is impractical for some types of abrasive wheels which have an inside core diameter of the abrasive annulus much larger than the diameter of the shaft upon which the wheel is to be mounted, since they require a large, expensive metal Wheel core which often increases the weight of the wheel to such an extent as to necessitate a heavy supporting shaft and massive wheel bearings. Large monolithic abrasive lwheels, such as sandstone wheels, which are frequently used in the paper industry, are often supported by massive wheel flanges rmly clamped against the two opposed side faces of the Wheel. This type of wheel mount has never proved entirely satisfactory owing to the fact that the wheel is supported only by a high clamping force exerted over a relatively small area at each end of the wheel. If one of these clamping flanges should slightly loosen, or if the grinding pressure should be excessive, the abrasive wheel weighing many tons might slip from its axial position and (Cl. 51-207J undoubtedly cause severe damage to the surrounding machinery as Well as to the operator, owing to its high speed of rotation. In recent years, some grinding wheels have been made of an annulus of abrasive segments and it has been proposed to rmly mount them upon a large metal drum or hub which in turn could be properly supported upon a shaft for rotation therewith. However, this means for mounting a segmental wheel upon a shaft has been somewhat unsatisfactory and expensive. These metal drums require careful machining and balancing, and often, as in the case of large pulpstones, add several tons to the Weight of the complete grinding wheel assembly.

The principal object of this invention is to provide a simple and inexpensive centering device for a grinding wheel which maybe made substantially integral therewith and which is provided with adjusting means whereby the grinding wheel may be minutely and quickly. adjusted to center it upon a supporting shaft.

It is a further object of this invention to provide a small centering member which may be secured within any abrasive Wheel having a relatively large hole and which may be radially adjusted to center the abrasive wheel upon various sizes of shafts.

To the accomplishment of these objects and such others as will be apparent to one skilled in the grinding art, I have provided a centering member adapted to be axially positioned within various types of abrasive wheels, such as natural sandstone or other monolithic wheels, or such as an articial grinding wheel which may comprise abrasive segments secured together by any suitable clamping means to form a grinding annulus. My centering member or hub preferably comprises a sleeve-like rough casting which requires no machining other than the tapping of a few holes for adjusting screws in each end thereof, since it does not directly engage nor does it even fit accurately against either the wheel or the shaft which passes therethrough and to which the wheel is secured for rotation. This centering member is positioned within and secured to the wheel by means of a layer of suitable cement, the thickness of which depends on the relative sizes of the hole within the wheel and the outside diameter of the centering member. Longltudinal ribs may be provided on the casting to aid in making the centering member an integral part of the wheel. An adjusting means is provided to locate the centering member on the wheel supporting shaft and this may comprise screws threaded in the casting Whichproject inwardly substantially radially to its axis. These screws may be minutely adjusted until the wheel supporting shaft is axially and positively aligned with the periphery of the grinding wheel.

One embodiment of this invention is shown in the accompanying drawing in which:

Fig. l'is a fragmentary view broken away to show applicants adjustable centering device utilized to support a segmental grinding wheel;

and

Fig. 2 is a sectional view taken along the line 2--2 of Fig. 1 showing the same grinding wheel mounted upon a shaft with the driving members and supporting shaft in position.

Referring more particularly to the drawing, one embodiment of this invention may comprise a centering and supporting means for a grinding wheel 10, which in the present instance is composed of a plurality of abrasive segments l1 secured to a central mandrel 13 by bolts 14 which are fastened to wedge blocks 15 arranged to engage reduced portions 16 of adjacent abrasive segments. A suitable filler 18, such as babbitt metal, lead, or a mixture of sulfur and coke, known as Lavasul, is cast within the crevices between the adjacent segments. Likewise the space between the mandrel 13 and the abrasive annulus has a suitable-cement 19 cast therebetween which is usually reinforced by metal rods 20, thereby forming a substantially integral and unitary wheel structure. This cement also provides end wheel faces against which Wheel flanges may be clamped to rotate the wheel in the customary manner.

To support such a segmental abrasive wheel upon a shaft, as well as natural stones or other monolithic wheels, applicant provides a centering member or hub 21 which may comprise a rough sleeve-like casting having a plurality of longitudinal ribs 22 protruding from its peripheral surface. The centering hub is positioned substantially coaxial With the grinding wheel upon a temporary locating member (not shown) and any suitable cement 23, such as Portland cement or concrete, is cast between the centering hub and the mandrel 13, .after which the temporary locating member is removed. 'Ihe heads of the bolts 14 and the longitudinal ribs 22 upon the centering hub 21 are firmly embedded within the cement which also adheres to the centering hub and to the mandrel, thereby serving to make the hub substantially an integral part of the grinding wheel. A plurality of adjusting screws 24 are threaded into each-end of the centering member and are arranged to project inwardly or radially to engage a shaft 26 insertable therebetween upon which the abrasive Wheel is mounted. By adjusting these screws relative to the shaft and to each other, the grinding wheel may be quickly and positively centered and balanced thereon. The adjusting screws are preferably located near the ends of the hub so as to be readily accessible, and, if the hub is shorter than the wheel width as in the present case, the cement 23 is cast so as to leave a recess 27 at each side of the wheel within which a wrench may be readily inserted to turn the adjusting screws. The grinding wheel may be driven in the accustomed manner by gripping the opposed wheel faces between two wheel flanges 28 and 29 which are threaded upon the shaft 26 upon a right-hand thread 30 and a left-hand thread 31 respectively.

It is readily apparent that my invention provides a quick, cheap and accurate method for nulus having a large center hole, a single-piece supporting a grinding wheel which has its entire weight evenly supported upon a short centering member. This member is notan expensive accurately machined, heavy cast-iron wheel hub,

as has been employed, since it may comprise a cheap, rough casting of any convenient size irrespective cf the shaft diameter or the diameter of the hole in the Wheel. This is a decided advantage over all prior wheel mounting devices since any 'suitable centering member may be mounted within any segmental or monolithic abrasive wheel which has a hole larger than the outside diameter of the centering member and which is longer than the centering member,

owing to the fact that this centering member is surrounded and firmly embedded within a cement which fills the entire space between it and the wheel. By mounting' adjusting screws at each end of the centering member to engage the shaft upon which the wheel is supported, I have provided a quick and simple method of positioning and centering any size of shaft which will pass through the centering member. -lurthermore, with such a mounting, the wheel may be easily and quickly removed from its shaft for any necessary repairs.v It should also be noted that such a wheel mount and centering construction is much lighter than previous wheel mounts and consequently the entire weight of the assembled grinding wheel may be maintained at a minimum. This is particularly advantageous in the case of large ymassive pulpstones weighing several tons since their supporting shafts and bearings may be made smaller thereby saving considerable `expense over the former heavy pulpstone installations.

It will also be apparent to those skilled in .this art that changes may be made in the details of construction of my centering member, since the above described and illustrated embodiment of this invention is intended solely as an explanation of its primary essentials, the features of which will be definitely expressed in the claims appended hereto. It will also be apparent that 'this centering device may b e applied to abrasive Wheels which grind either upon the peripheral face or upon one plane end face and that it may be applied to various sizes, shapes and types of Wheels.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A grinding wheel comprising an abrasive ancentering hub of smaller diameter than the hole which is located therein, a suitable cement positioning said hub within the annulus, and readily accessible adjusting screws afxed to the centering hub and projecting inwardly therefrom which are engageable with a supporting shaft whereby the grinding Wheel may be adjustably centered upon said shaft.

2. A grinding wheel comprising an annular abrasive body having a large center hole, a hub '140 of smaller diameter than said hole and located therein, a layer of cement around the hub whichl secures it to and locates it within the abrasive body, a shaft loosely mounted within the hub, adjustable means for mounting the hub on said shaft irrespective of the size of the latter and driving plates adjustably mounted on the shaft which clamp against the sides of the wheel and drive it.

3. A support for grinding wheels having cen-" romana ter holes of various sizes comprising an annular single-piece hollow hub of a size adapted to freely t within. such a Wheel and loosely around a supporting shaft, means to secure said hub rigidly to the wheel, and radially adjustable centering devices on the hub which project inwardly and serve to mount said hub and Wheel on the shaft.

4. An abrasive wheel having a large hole, a Wheel supporting hub of considerably smaller diameter which is axially centered Within and spaced from the Wheel, a layer of cement integrally uniting the hub to the Wheel, a wheel supporting shaft Within the hub, adjustable means affixed to the hub which mount the hub on the shaft and may be used to exactly center the wheel upon said shaft and driving plates adjustably mounted on the shaft which engage the end faces of the Wheel and serve to rotate it.

5. A grinding Wheel comprising an abrasive annulus having a relatively large center hole, a hub therein of considerably smaller size which is radially spaced from the abrasive annulus, a multiplicity of ribs upon the hub and prolan axially centered hub therein of considerably smaller size which is radially spaced from the abrasive annulus, a plurality of ribs projecting from the peripheral surface of the hub, a layer of cement Within which the ribs are rmly embedded and integrally uniting the hub to the abrasive annulus, and adjusting screws at each end of the hub engageable with a supporting shaft passing through the hub which may be adjusted relative to each other and thereby accurately center the grinding Wheel upon the shaft. c

THURE LARSSON. 

